The present invention relates to a saw blade for preventing undercut to be used for cutting a hard and rough material like green concrete and asphalt and more particularly a saw blade for preventing undercut characterized in that out of the sludge discharging slots arranged together with undercutting segments and general cutting segments on the circumference of a steel wheel, those slots located in the rear faces of the undercutting segments are dimensioned larger or wider than the slots in the rear faces of the ordinary cutting segments in order to prevent the breakage and falling-off of the undercut preventing cutting segments and ordinary cutting segments.
According to a conventional undercut preventing saw blade which is shown in the attached drawing of FIG. 1, on the circumference of a steel wheel 2, there are alternately arranged ordinary cutting segments 3 containing diamond powders and undercutting segments 4 dropped on one of the opposite sides as well as sludge discharging slots 5 each with a specified opening formed between respective neighboring cutting segments.
In the case that only uniform ordinary slots are formed behind every ordinary and undercut preventing cutting segments in the direction of rotation, however, the following problems are caused when using the saw blade.
In case that all are ordinary slots, an undercut preventing cutting segment the lateral cross section of which is larger than that of an ordinary cutting segment experiences more cutting resistance than an ordinary cutting segment.
As the result, when the material being cut is hard and coarse like asphalt or concrete, some of the sludge including powders and scraps of the material are choked in the clearance between the saw blade, particularly the undercutting cutting segments, and the material being cut failing to rapidly discharge as if it is attached on the surfaces of the saw blade. Thus, the sludge on the peripheral surfaces of the blade at the area of undercutting cutting segments exerts radially outward force upon the undercutting cutting segments through the centrifugal force due to the rotating saw blade resulting in occasional breakage or falling-off of some undercutting cutting segments.
The present invention which was created to deal with the above described circumstance intends to provide a saw blade for preventing undercut wherein out of the sludge discharging slots arranged together with undercutting cutting segments and ordinary cutting segments on the circumference of a steel wheel, those slots located at the rear faces of the undercutting cutting segments are dimensioned relatively larger or wider in order to prevent the breakage and falling-off of the undercut preventing cutting segments and ordinary cutting segments.
To that end, there is provided a saw blade including a steel wheel and on the circumference of said steel wheel plural ordinary cutting segments and undercut preventing segments, two or more segments of one type being arranged alternately with one or more segments of the other type, characterized in that at the rear faces of respective ordinary cutting segments narrow slots with a predetermined narrow clearance are formed for minor discharge of cut sludge and behind respective undercut preventing segments wide slots with a larger clearance than the narrow slots are formed for major discharge of cut sludge, the directions being based on the rotation of the blade wheel.